Bus driver Eric Norsworthy closes a window on the California Teachers Association bus parked at the Butte Community College campus near Oroville, Calif., May 5, 2008. One of the most powerful unions in California, the CTA held a six-week statewide bus tour to rally against Gov. Arnold Schwarzenegger’s proposal to cut $4.4 billion in education spending in the 2008-09 state budget.

It should come as no surprise that a California public employee union would be dubbed the “worst union in America.” In the current quarterly edition of City Journal, writer Troy Senik bestows that label on the California Teachers Association, opining that the CTA has not only “betrayed schools” but also helped “cripple the state.”

The 340,000-member CTA – the state’s largest labor union and an affiliate of the nation’s largest union (the 3.2 million-member National Education Association) – is far more than an advocate for teachers; it is an instrument for political dominance across a spectrum of issues in California and elsewhere. Senik’s characterizes the CTA as “a political behemoth that blocks meaningful education reform, protects failing and even criminal educators and inflates teacher pay and benefits to unsustainable levels.”

Activism by the CTA dates back to Gov. Jerry Brown’s first year of his initial eight-year administration, Senik argues, when Brown in 1975 “signed the Rodda Act, which allowed California teachers to bargain collectively.” This initiated the political dominance of unions, whose members would vote in blocs in local school board elections, allowing teachers to “handpick their own supervisors,” a strategy that remains rampant in school districts today.

It’s been a winning long-term strategy for the CTA because school board members can become city council members who can become state legislators who can become members of congress, governors, etc. Remember that Jerry Brown’s first elective office was as a member of the Los Angeles Community College Board of Trustees, from 1969-71.

The CTA’s other weapon has been political cash, collected as mandatory dues from its army of members, allowing the union to plan and strategize priorities years in advance.

In 1993 for example, the CTA spent $12.5 million to block a school-choice ballot initiative that would have given parents and students the ability choose their school – private or public – regardless of where they lived. The CTA, Senik wrote, even “bullied members of the business community who contributed” to the choice effort, including California’s iconic In-N-Out burger chain, which donated to support the measure. In response, “the CTA threatened to use its market power – the teachers’ retirement fund, CalSTRS, is the second-largest pension fund in the nation – to crush the value of the burger chain’s stock.” And the union threatened to push “schools to drop contracts with companies” which similarly supported the initiative.

That’s only one of many examples that Senik outlines: in 1998 the CTA spent $7 million to defeat an education reform proposition that linked teacher reviews to student performance and would have made teachers pass a discipline-specific credentialing test; in 2002 the CTA spent $26 million to defeat another school-choice proposition; and in 2005 “the CTA came up with a colossal $58 million – even going so far as to mortgage its Sacramento headquarters – to defeat” a slew of reform initiatives proposed by Gov. Arnold Schwarzenegger.

In the decade ending in 2010, the CTA spent more than $200 million on lobbying, political expenditures and campaign contributions, more than any other entity in California. In 2011, it spent $6,574,257, a lobbying tab more than $1.5 million greater than the second-place spender.

Given its bankroll, the CTA has become the spear tip for leftist governance in the state. That, and, as Senik notes, the teachers union “funds an array of liberal causes unrelated to education, with the goal of spreading around enough cash to prevent dissent from the Left.” CTA is the most-special special interest in the state Capitol.

If the state weren’t in constant financial upheaval, and public education here met high standards, one might make a favorable case for the CTA’s disproportionate influence in the state. But California schools are among the worst-ranked in the nation.

In his new book, “Eureka! How to fix California,” famed economist Art Laffer noted that while educational outcomes are dismal in the state, “teachers in California are actually paid higher salaries than the U.S. average.”

They are “the highest-paid teachers in the nation,” at an average of $68,000 annually, according to Senik. And that doesn’t take into account pension benefits, which typically allow teachers to retire after 30 years with 75 percent of their salary.

To achieve serious reform not only of the state’s education system but also its once-golden economic standing, Sacramento lawmakers will have to break the cycle of subservience to special interests, starting with the most dominant union in America.